In 1965, marchers for voting rights crossed the Edmund Pettus Bridge in Selma, sparking an explosion heard and seen around the world. Marchers crossed again Sunday, in an exercise that was more celebration and commemoration than confrontation. This year, with Donald Trump in the White House and state legislatures in Alabama and elsewhere intent on making it harder to vote, the Bridge Crossing commemoration took on a new urgency. Keep on marching, the leaders urged, keep on moving to a brighter, more free tomorrow.